The Sitemap XML protocol is also extended to provide a way of listing multiple Sitemaps in a 'Sitemap index' file. The maximum Sitemap size of 50 MiB or 50,000 URLs means this is necessary for large sites. An example of Sitemap index referencing one separate sitemap follows.
Cultural or artificial eutrophication occurs when human activity introduces increased amounts of these nutrients, which speed up plant growth and eventually choke the lake of all of its animal life.n nature, eutrophication is a common phenomenon in freshwater ecosystems and is really a part of the normal aging process of many lakes and ponds. Some never experience it because of a lack of warmth and light, but many do.
Major sources of excess nutrients which are responsible for eutrophication are agricultural fertilizers, livestock wastes and domestic sewage. Agricultural fertilizers provide inorganic nutrients like nitrates and phosphates which play an important role in this process.utrophication can be of two types.Man madeWhen the waste materials like sewage effluents are thrown in the water than it contains some nutrients which causes this problem.